What should I eat before my 1 hour glucose test?

Quick Answers

Here are some quick tips for what to eat before a 1 hour glucose test:

  • Eat normal amounts of carbohydrates in your meals leading up to the test
  • Avoid large amounts of sugar and refined carbs right before the test
  • Eat a mix of protein, fat and complex carbs
  • Hydrate well with water
  • Avoid caffeine before the test

The 1 hour glucose test is an important screening tool used during pregnancy to check for gestational diabetes. It involves drinking a sugary drink and having your blood sugar measured after 1 hour to see how your body processes the sugar.

What you eat in the days and hours leading up to the test can impact the results. Following the right diet can help ensure you don’t get false positive or false negative results.

This article will provide tips on what to eat before the 1 hour glucose test based on expert recommendations. Proper nutrition is key to making sure the test accurately reflects how your body metabolizes sugar when pregnant.

Why the 1 Hour Glucose Test is Performed

The 1 hour glucose test, also called the glucose challenge test or GCT, is typically performed between 24-28 weeks of pregnancy. It checks how your body processes a set amount of glucose from the sugary drink you consume.

This test is important because:

  • It screens for gestational diabetes, which occurs in 2-10% of pregnancies
  • Untreated gestational diabetes can lead to complications like preeclampsia, excess fetal growth, and c-section delivery
  • Catching it early allows steps to be taken to manage blood sugar and improve outcomes

If you fail the 1 hour glucose test, meaning your blood sugar is too high, you’ll likely have to take a 3 hour glucose tolerance test to definitively diagnose if you have gestational diabetes.

How the Test Works

For the 1 hour glucose test, you will be instructed to fast for 8-14 hours beforehand. At your prenatal visit, you will drink a sugary solution that contains around 50 grams of glucose.

After exactly 1 hour, a blood sample will be taken to measure your blood sugar level. A reading of 130-140 mg/dL or higher indicates you may have impaired glucose metabolism and will require further testing.

Eating properly leading up to the test ensures your body has time to process any carbohydrates consumed. This helps prevent skewed results from sudden spikes or drops in blood sugar before the test.

Foods to Eat Before the Test

Here are some healthy foods to focus on in the days and hours leading up to your 1 hour glucose test:


  • Lean meats like chicken, turkey, fish
  • Eggs
  • Tofu
  • Beans, lentils, legumes
  • Nuts and seeds
  • Low-fat dairy like yogurt and milk

Protein helps stabilize blood sugar and provides lasting energy. It also slows digestion, preventing spikes in blood sugar.

Healthy Fats

  • Avocados
  • Olive oil
  • Nuts and nut butters
  • Seeds
  • Fatty fish like salmon

Like protein, healthy fats promote steady blood sugar levels and help you stay full between meals.

High Fiber Complex Carbs

  • Whole grains like oats, quinoa, brown rice
  • Starchy vegetables like sweet potatoes, squash, peas
  • Fruits like apples, pears, berries
  • Beans and lentils

Complex carbohydrates are digested slowly, preventing spikes in blood sugar. Fiber also slows digestion and absorption of carbs.


Staying hydrated is key before the test. Dehydration can cause false high blood sugar readings. Aim for 8-10 glasses of fluids daily, focusing on water.

Foods to Avoid Before the Test

On the flip side, here are some foods it’s best to limit leading up to your glucose test:

Sugar and Sweets

  • Candy
  • Soda
  • Fruit juice
  • Smoothies
  • Cakes and cookies
  • Chocolate
  • Ice cream
  • Sweetened yogurt

Large amounts of sugar can cause rapid spikes and drops in blood sugar, interfering with test results.

Refined Carbohydrates

  • White bread, pasta, rice
  • Pastries
  • Chips
  • Crackers
  • Cereals with added sugar

Refined carbs act similar to sugar in the body, causing rapid swings in blood glucose.

Fried Foods

  • French fries
  • Fried chicken
  • Potato chips
  • Doughnuts
  • Deep fried foods

Fried foods are high in unhealthy fats that can contribute to unstable blood sugar.


Caffeine found in coffee, tea, soda and energy drinks can transiently raise blood sugar. It’s best avoided before glucose testing.

Sample Meal Plan

Here is a sample meal plan for what to eat in the 3 days leading up to your 1 hour glucose test:

3 Days Before Test


  • 2 eggs scrambled with 1/2 cup spinach and 1/4 avocado
  • 1 slice whole wheat toast with 1 tbsp natural peanut butter
  • 1 cup berries


  • Tuna salad sandwich on whole grain bread with lettuce and tomato
  • 1 cup vegetable soup
  • 1 pear


  • 3 oz grilled salmon
  • 1 cup quinoa
  • 1 cup roasted Brussels sprouts
  • Green salad with vinaigrette dressing

2 Days Before Test


  • 1/2 cup plain Greek yogurt with 1/4 cup berries and 1 tbsp chopped walnuts
  • 1 slice whole wheat toast with 1 tbsp almond butter


  • Lentil soup
  • Mixed greens salad
  • 1 oz low-fat cheese
  • Whole grain crackers


  • 3 oz baked chicken breast
  • 1/2 cup brown rice
  • 1 cup roasted vegetables

Day Before Test


  • 2 hardboiled eggs
  • 1 slice whole grain toast
  • 1/2 banana


  • Turkey and avocado sandwich on whole wheat bread
  • Carrot sticks
  • 1 cup edamame


  • 3 oz grilled chicken
  • Baked sweet potato
  • Steamed broccoli

Tips for Day of Glucose Test

Here are some additional tips for the day of your 1 hour glucose screening:

  • Fast for 8-14 hours before the test, only drinking water
  • Avoid caffeine on the day of the test
  • Stick to clear liquids like water, broth, popsicles until the test
  • Avoid strenuous exercise before the test
  • Don’t smoke before the test
  • Relax and try to stay calm – stress can affect blood sugar

Supplements and Medications

Certain supplements and medications can also impact glucose test results. Be sure to discuss the following with your provider before the test:

  • Prenatal vitamins – may contain glucose
  • Iron supplements
  • Steroids
  • Beta-blockers
  • Diuretics
  • SSRIs
  • Other prescription medications

Your provider may recommend adjusting the dose or stopping these temporarily to prevent interference.

Importance of Accurate Test Results

Eating a balanced, healthy diet in the days leading up to your 1 hour glucose test will help ensure you get accurate results.

If results are normal, you likely don’t have gestational diabetes and won’t require additional testing or treatment.

Abnormal results mean further screening is needed to properly diagnose and manage gestational diabetes for the health of you and your baby.

Work with your prenatal care provider to determine the best nutrition plan for you before the glucose test and throughout your pregnancy.


Preparing properly for your 1 hour glucose test involves being mindful of your diet in the days beforehand. Focus on nutrient-dense foods like lean proteins, healthy fats, high fiber carbs and staying hydrated.

Limit sugar, refined grains, fried foods and caffeine right before the test. Stick to a balanced meal plan and fasting instructions to help ensure accurate results.

Talk to your provider if you have any concerns about what to eat in preparation for this important screening test for gestational diabetes during pregnancy.

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